The present invention relates generally to welding wire feeders. More specifically, it relates to a modular portable welding wire feeder housed in an instrument case and a method of modifying an instrument case to house a welding wire feeder.
Housings for welding wire feeders are typically made from either metal or plastic. Non-portable wire feeders, for example, typically have metal housings made from sheet metal. The sheet metal is bent and punched to form a custom housing for each wire feeder model. These non-portable wire feeders are generally used indoors at a single location.
Portable wire feeders, on the other hand, typically have handles and are transported from location to location. Portable wire feeders are generally used outdoors where they are exposed to the elements. This is especially true in the ship building and construction industries. Plastic housings are ideally suited for this type of usage because they are impact and corrosion resistant. Plastic housings also act as an electrical insulator between the internal wire feeder components and the external working environment such as the metal on ships.
Plastic housings for welding wire feeders have typically been custom made using rotational molding techniques, although injection molding and compression molding have also been used. Rotational molding is desirable over injection and compression molding because of the lower tooling costs involved. Typical wire feeder sales volumes do not justify high tooling costs.
Prior art custom wire feeder housings made using rotational molding typically include a three dimensional main housing portion (e.g. base) and a cover that is substantially flat (e.g. substantially two dimensional in shape). A large opening is cut into one side of the main portion of the housing to allow for access to the wire feeder components. The cover is hinged to the main portion and closes the opening. One such prior art wire feeder that uses this type of housing is the S-22P12 wire feeder manufactured by Miller Electric Mfg Co., Appleton Wis.
Rotationally molded housings suffer from many drawbacks, however. Rotationally molded parts, for example, vary greatly from part to part due to uncontrollable warpage and shrinkage. The various parts that make up a complete housing (e.g. the cover and main housing portion), as a result, do not necessarily fit well together. Assembling these housings is difficult and the overall quality of the housing is affected.
Rotationally molded housings are also not as sturdy as comparable housings made using injection or compression molding. The covers, for example, tend to be flexible and flimsy making it difficult to tightly seal the mating seam between the cover and the base. These housings are less sturdy in part because different polymers are used in rotational molding as compared with injection and compression molding. It is also easier to mold reinforcing structures into housings made form injection molding or compression molding, such as reinforcement ribs.
Other problems with rotationally molded housings include the large cycle time involved in making rotationally molded parts and the numerous secondary operations, such as machining operations, that are required to add holes to these parts.
As an alternative to rotational molding, some prior art custom made wire feeder housings have been molded using injection molding or compression molding. Custom housings produced using these techniques have the potential to be much more rugged and of higher quality than those made using rotational molding.
The drawback to using these molding techniques, however, lies in the high cost of the tools that are required. An injection molding tool for a custom molded wire feeder housing can cost hundreds of thousands of dollars. Such a high cost typically cannot be justified given the typical sales volumes for welding wire feeders.
In those situations where injection or compression molding have been used, only the main portions of the housing have been injection molded (e.g. the base and the cover). These housing parts have typically been simple in design to keep tooling costs to a minimum. The remaining parts of the housing, such as handles, latches, and hinges, have traditionally been made of metal to further reduce tooling costs for the overall feeder housings.
It is desirable to have a plastic housing for a welding wire feeder that is as rugged and well made as those made using injection molding or compression molding. Preferably the housing can be made without incurring the high cost of tooling that is associated with these types of molding processes.
Injection molded off-the-shelf instrument cases (and tool boxes) for use in a wide variety of applications are commercially available from numerous manufacturers. These cases are available in many different sizes. The various components of these instrument cases, such as the cover and the base, the handle, the latches, and the hinges are all typically molded using injection molding or compression molding techniques.
Many of these components are molded as integrated parts. For example, the hinges are integrally molded as part of the base and the cover. Both the cover and the base include sidewalls and are three dimensional in shape. Reinforcement ribs are also integrally molded into the cover and base portions of the case. These cases are very rugged and of high quality.
Using injection molding or compression molding to create these cases is cost justifiable because these cases are marketed for use in a wide variety of applications and industries. These cases are typically used for carrying or storing instruments and equipment of all kinds, including tools, cameras, computers, measurement equipment and testing equipment. A large quantity of these cases are sold as a result.
The particular instrument or apparatus carried in these cases is typically removed from the case for use outside of the case. Alternatively, access to an instrument is provided by opening the case and the instrument is used while in the case but with the case open.
Instruments stored or carried in these cases are generally not used with the case closed (e.g. the case is not used as a housing). This is because these cases as commercially sold off-the-shelf do not allow for the instrument to be used with the case closed. There is typically no way to access the instrument with the case closed. Also, there is no way to provide inputs to the instrument or to receive outputs from the instrument with the case closed.
It is desirable, therefore, to modify these injection molded, rugged, high quality, instrument cases to house a welding wire feeder. Preferably, the case is modified to house the various wire feeder components inside and to allow for operation of the wire feeder with the case closed. The instrument case is also preferably modified to receive the various wire feeder inputs and to provide the various wire feeder outputs while the case is closed.
It is also desirable to have portable wire feeders that are small, lightweight, and easily transported. In the ship building industry, for instance, it is desirable to have a portable wire feeder that is sized to fit through the port hole of a ship. Preferably, these wire feeders weigh 25 pounds or less (excluding the weight of the spool of weld wire). Lightweight instrument cases are also well suited for this purpose.
Another problem with prior art wire feeders in general is that they are difficult to service and repair, especially in the field. Typically, the various wire feeder components (e.g. wire drive assemblies, spool supports, circuit boards, gas valves, etc . . . ) in prior art wire feeders are separately mounted inside of the wire feeder housing each with its own set of fastening hardware. Removal of these components is difficult and time consuming because a large number of fasteners must be removed. Also, some of these fasteners are difficult to reach inside of the housing. These components, as a result, are left in the wire feeder housing during initial testing and servicing of the overall wire feeder. This makes servicing of prior art wire feeders difficult. This is especially true in the case of portable wire feeders which are typically small and compact in size.
Replacing a damaged prior art wire feeder housing is also difficult because each of the various wire feeder components must be individually removed from the damaged housing and remounted in the new replacement housing. Finally, it is also difficult to design new housings for these prior art wire feeders to meet specific customer requirements. This is because the various wire feeder components are typically mounted directly to the inside of the housing itself which makes for a complicated housing design.
It is desirable, therefore, to have a wire feeder that is easily serviced and repaired. It is also desirable to have a wire feeder housing that is easy to replace when damaged. Preferably, such a wire feeder is modular in construction. All or most of the various wire feeder components are preferably assembled into a single chassis assembly. The chassis assembly, in turn, is preferably mounted to the inside of the housing in a simple and uncomplicated manner using a minimal number of fasteners. The chassis assembly preferably can be easily and quickly removed from the housing as a single unit during testing, servicing or housing replacement.
According to a first aspect of the invention, a portable welding wire feeder includes an instrument case. A spool support and a wire drive assembly are mounted in the instrument case. The spool support is disposed to support a spool of weld wire. The wire drive assembly is disposed to receive the weld wire from the spool and provide the weld wire to a welding gun.
A chassis assembly is mounted to the instrument case in one embodiment and includes the spool support and the wire drive assembly. The instrument case includes at least one welding input interface disposed to receive a welding input in one embodiment. In an alternative embodiment, the instrument case includes at least one welding output interface disposed to provide a welding output. The portable welding wire feeder includes a control panel mounted on the outside of the instrument case in yet another embodiment.
A weld power delivery device is mounted in the instrument case in one embodiment. The weld power delivery device is disposed to receive weld power from a welding power supply and provide the weld power to the welding gun.
The instrument case includes a welding gun interface in one embodiment and the wire drive assembly is disposed to provide the weld wire to the welding gun through the welding gun interface. In another embodiment, the instrument case includes a cover and a base connected to the cover. The cover and the base open and close along a mating seam. The welding gun interface interrupts the mating seam in this embodiment.
The portable welding wire feeder is capable of operation with the instrument case closed in yet another embodiment.
According to a second aspect of the invention, a housing for a portable welding wire feeder includes an instrument case having a cover and a base connected to the cover. The cover and the base open and close along a mating seam. The instrument case includes at least one welding input interface disposed to receive a welding input and at least one welding output interface disposed to provide a welding output.
The at least one welding input interface includes a weld power interface disposed to receive weld power from a welding power source in one embodiment. The at least one welding output interface includes a welding gun interface disposed to provide welding power to a welding gun in a second embodiment. The welding gun interface interrupts the mating seam in another embodiment.
The at least one welding input interface includes a shielding gas interface in one embodiment. The shielding gas interface is disposed to receive shielding gas from a source of shielding gas. A control panel interface is provided on the instrument case in a third embodiment. The control panel interface is disposed to receive a control panel in this embodiment.
According to a third aspect of the invention, a method of modifying an instrument case to house a welding wire feeder includes adapting the instrument case to hold a spool support and a wire drive assembly. The spool support is disposed to support a spool of weld wire. The wire drive assembly is disposed to receive the weld wire from the spool and provide the weld wire to a welding gun.
The instrument case is adapted for mounting a chassis assembly thereto in one embodiment. The chassis assembly includes the spool support and the wire drive assembly in this embodiment. In an alternative embodiment, the method includes adapting the instrument case to hold a weld power delivery device. The weld power delivery device is disposed to receive weld power from a welding power supply and provide the weld power to the welding gun. The instrument case is adapted to receive a control panel mounted on the outside of the instrument case in an alternative embodiment.
A welding gun interface is added to the instrument case in yet another embodiment. The welding gun interface is disposed to provide the weld wire from the wire drive assembly to the welding gun. The instrument case is adapted such that the welding wire feeder is capable of operation with the instrument case closed in one other embodiment.
According to a fourth aspect of the present invention, a method of converting an instrument case into a welding wire feeder housing includes adapting the instrument case to receive weld power from a welding power source, adapting the instrument case to provide weld power to a welding gun, and adapting the instrument case to provide a weld wire to a welding gun.
The instrument case is adapted to receive shielding gas from a source of shielding gas and to provide shielding gas to a welding gun in one embodiment. The instrument case is adapted to receive a control panel in another embodiment.
According to a fifth aspect of the invention, a method of converting an instrument case into a welding wire feeder housing includes adding at least one welding input interface and at least one welding output interface to the instrument case. The at least one welding input interface is added to receive a welding input. The at least one welding output interface is added to provide a welding output.
The at least one welding input interface includes a weld power interface in one embodiment. The weld power interface is disposed to receive weld power from a welding power source. The at least one welding output interface includes a welding gun interface in another embodiment. The welding gun interface is disposed to provide welding power to a welding gun.
The at least one welding input interface includes a shielding gas interface to receive shielding gas in one embodiment. A control panel interface is added to the instrument case to receive a control panel in an alternative embodiment.
According to a sixth aspect of the invention, a modular welding wire feeder includes a housing and a chassis assembly attached to the housing. The chassis assembly includes a chassis frame and at least two welding wire feeder components attached to the chassis frame.
One of the at least two welding wire feeder components is a wire drive assembly in one embodiment. Another one of the at least two welding wire feeder components is a weld power delivery device, a spool support assembly or a circuit board in other embodiments. The at least two welding wire feeder components is at least three welding wire feeder components in one embodiment and is at least four welding wire feeder components in another embodiment. The chassis assembly is attached to the housing at four or less locations in another alternative embodiment.
Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.